Semiconductors form the basis of modern electronics. Possessing physical properties that can be selectively modified and controlled between conduction and insulation, semiconductors are essential in most modern electrical devices (e.g., computers, cellular phones, photovoltaic cells, etc.). Group IV semiconductors generally refer to those elements in the fourth column of the periodic table (e.g., carbon, silicon, germanium, etc.).
Chemical vapor deposition (CVD) is often used in the processing of semiconductors. In a typical CVD process, the wafer (substrate) may be exposed to one or more volatile precursors, which react and/or decompose on the substrate surface to produce the desired deposit. However, commonly used CVD processes may be problematic. For example, CVD processed tend to have slow deposition rates, which limit the cost-effective fabrication of a range of film thicknesses. In addition, large components are often difficult to position in CVD chambers, high processing temperatures must generally be used, and substantial chemical wastes are often produced.
An alternate manufacturing technique involves the deposition and densification on a wafer of nanocrystalline silicon particles formulated in a solvent-binder carrier. For example, nanoparticles may be mixed with organic binders (e.g., polystyrene) in solvents (e.g., chloroform) to produce semiconductor inks that were printed on bond paper. See WO Patent Application No. 2004IB00221.
Alternatively, composite thin films of both unhydrogenated passivated Group IV semiconductor nanoparticles (having diameters below 10 nm) and hydrogenated amorphous Group IV materials may be first deposited and then sintered on a wafer. Consequently, the combination of smaller nanoparticles with larger Group IV materials allows the processing temperature to be decreased to about 400° C. See U.S. Patent Application No. 20060154036.
However, in both of these examples, significant amounts of organic materials are used in the Group IV semiconductor thin film layers, leading to high processing costs, and the composites formed are substantially different than the well-accepted native Group IV semiconductor thin films.
Therefore, there is a need for native Group IV semiconductor thin films fabricated with relatively high volume processing methods.